1. Field of Invention
The invention relates to data management and, in particular, to a method for managing data which is stored in the flash memory.
2. Related Art
Flash memory is a kind of storage system with the advantages of high access speed and high stability. It is non-volatile memory. That is, once data are stored in the flash memory, it no longer needs power to maintain the data.
The structure of the flash memory is in units of blocks. Each block is further divided into pages or sections. If data need to be written into the flash memory, a data writing command is executed to write data in an external buffer into the buffer of the flash memory before writing it into the flash memory. Under the condition that NOP is 1, the data in the memory page can be only written once. In practice, it is likely to occur that data cannot fully occupy a flash memory block or the data storage is not continuous. In these cases, the storage efficiency of the flash memory is reduced. Data defragmentation is employed to solve this problem. However, it requires a lot of time to reorganize data in the flash memory. In particular, once a destination address of the external buffer is assigned to the data, the current structure does not allow one to change the destination address of the data already stored in the buffer of the flash memory or read the data out of the buffer of the flash memory. Moreover, such a structure is not suitable for speeding up the data defragmentation.
It is therefore desirable to provide a new method for managing flash memory data to prevent from spending a lot of time re-organizing data therein because of loose or discontinuous data distribution. The data storage ability of the flash memory is better optimized by reducing the dependence on the external buffer.